This invention relates to a ventilating system for a watercraft and more particularly to an improved engine compartment ventilating for such watercraft and an improved exhaust system for this type of watercraft.
As is well known, engines powered by internal combustion engines that are mounted inboard of the hull and within an engine compartment require adequate ventilation of the engine compartment. It is desirable to ensure that adequate air can reach the engine for combustion and also so as to purge the engine compartment from unwanted vapors. This problem, although easily handled with larger watercraft, presents a number of problems in conjunction with a smaller type of watercraft known as a "personal watercraft."
Personal watercraft are a relatively small type of watercraft wherein the rider sits more upon than in the watercraft. This type of watercraft is designed to be operated primarily by a single rider although accommodations are frequently made for one or more passengers in addition to the operators. With this type of watercraft, the engine compartment is frequently formed below the rider's area or immediately forwardly of it.
This type of watercraft is quite sporting in nature and thus the rider and passengers frequently wear swimming suits when riding this type of watercraft. Thus, they expect to receive a fairly large amount of water spray during the watercraft operation. As a result of this, there is a fair amount of water spray around the environment of the watercraft and this can easily enter the engine compartment through the ventilating system. Of course, it is desirable to protect the engine and its auxiliaries from this water. Various arrangements have been proposed, therefore, for providing ventilation of the engine compartment while, at the same time, precluding water ingestion.
With the small type of watercraft involved, it is important to ensure adequate ventilating airflow but also to ensure that water will not enter the engine compartment through the ventilating system. For the reasons aforenoted, this is particularly difficult with personal-type watercraft.
It is, therefore, a principal object of this invention to provide an improved engine compartment ventilating system for a personal watercraft.
It is a further object of this invention to provide a ventilating arrangement for a personal watercraft that will provide adequate ventilation and also will provide good assurance that water will not be inadvertently drawn into the engine compartment along with the ventilating air.
With this type of watercraft, the hull is generally made up of two major components, a lower hull under portion and an upper deck portion. The engine compartment is normally formed between these two hull portions. Because of this type of construction, it is relatively difficult to provide a good ventilating system that will achieve the aforenoted effects.
It is, therefore, a still further object of this invention to provide an improved hull configuration for this type of watercraft wherein an adequate and yet highly waterproof ventilating system is provided.
In addition to the problem of adequate ventilation of the engine compartment, the handling of the exhaust gases for this type of watercraft also presents problems that are unique because of the size and nature of use of this type of watercraft. This type of watercraft is often powered by a jet propulsion unit which is mounted in a tunnel to the underside of the hull. This type of propulsion unit offers a number of advantages but the intrusion of the tunnel into the hull area further reduces the space available for the exhaust system components.
Also, it is the general practice to discharge the exhaust gases to the atmosphere from marine engines either at or below the water level. This assists in the silencing of the exhaust gases. Furthermore, it is the normal practice to discharge the water from engine cooling jacket into the exhaust system so as to simplify the fluid handling and to cool the exhaust gases and provide additional silence.
All of these factors, however, add to the risk that water may enter the engine through the exhaust system. This problem is further compounded by the fact that this type of watercraft frequently may become capsized and the occupants and users recognize that this is a distinct possibility. Therefore, some type of arrangement is normally incorporated not only for silencing the exhaust gases but also for ensuring against water entering the engine through the exhaust system. Of course, these components have specific spatial requirements and this gives rise to the design problems aforenoted.
It is, therefore, a still further object of this invention to provide an improved exhaust system for a personal watercraft.
It is a further object of this invention to provide an exhaust system for a personal watercraft that can have sufficient length and yet incorporate devices for ensuring that water cannot reach the engine through the exhaust system including water that may be discharged from the engine cooling jacket into the exhaust system.